Question 25

Sound waves that are closer together have a higher pitch.

When sound waves are closer together, they have a higher frequency, which results in a higher pitch. This phenomenon is a fundamental aspect of the Doppler Effect, as described in the extract.

A) Those waves that are closer together

This option is correct because closer sound waves correspond to a higher frequency, resulting in a higher pitch. The extract clearly states that as the locomotive or ambulance moves toward the listener, the sound waves in front of it are pulled closer together, leading to a higher pitch being perceived.

B) Those waves that are farther apart

This option is incorrect since sound waves that are farther apart have a lower frequency, which results in a lower pitch. The extract explains that as the moving object moves away from the listener, the sound waves behind it are spaced farther apart, leading to a lower pitch.

C) Those waves that travel a long distance

This option is incorrect because the distance that sound waves travel does not directly affect their pitch. The pitch is determined by the frequency of the waves, which is influenced by their spacing rather than the distance traveled.

D) Those waves that travel a short distance

This option is also incorrect. Similar to option C, the distance traveled by sound waves does not inherently determine their pitch. The crucial factor is the frequency of the waves, which is related to their spacing rather than the distance they cover.

Conclusion

Option A is definitively correct because it aligns with the principles of the Doppler Effect, where closer waves result in a higher pitch. All other options fail to recognize the relationship between wave frequency and pitch, as they either misstate the effects of wave spacing or suggest irrelevant factors like travel distance.